1. Field of the Invention
The present invention relates to bag with longitudinal gusset folds, at least comprising a central and two outer longitudinal gusset fold edges which bound a first and a second gusset fold part, by providing a continuously supplied tubular plastic foil by heatsealing with a first transverse bottom seal which extends across the entire width of the tubular foil and moving the tubular foil over a predetermined distance to another sealing position.
2. Description of the Prior Art
A bag of this type is known in the prior art. In the prior art methods the first transverse bottom seal is produced by heatsealing the various different foil layers across the entire width of the bag after having applied lower and upper fold part seals slopingly extending with respect to one another, preferably under an angle of 45.degree., at both ends of the bag.
The first fold part seals contact the first transverse bottom seal so that a filled bag can be given a block shape at the bottom side. The second fold part seals likewise form, together with a final heatseal to be applied, a block bottom, thus causing a filled bag to have a block shape at either side.
This bag represents the disadvantage that in the filling procedure of the bag filler material to be packed in such a bag is able to penetrate in the pockets existing between the upper fold part seals and the outer longitudinal gusset fold edges. Of course this filler material will impair the quality of the seal to be applied for closing the bag, the more so as in the gusset fold region four foil layers have to be heatsealed to each other and in the central part only two.
Of course one might position the filling mouth of the filling machine at a lower level in the bag but this decreases the filling capacity of a bag.
Furthermore the pockets cannot be removed as these pockets are necessary for seizing a bag during the filling procedure.
The additional seals should be close to the inner gusset fold edges in order to obtain an improved closing seal. If the additional seal would be far from the inner gusset fold edge much filler material would be present between the inner surfaces of the outer foil layers and opposite gusset fold part.